Methods and apparatus to extract a pitch-independent timbre attribute from a media signal

Abstract

Methods and apparatus to extract a pitch-independent timbre attribute from a media signal are disclosed. An example apparatus includes an audio characteristic extractor to determine a logarithmic spectrum of an audio signal; transform the logarithmic spectrum of the audio signal into a frequency domain to generate a transform output; determine a magnitude of the transform output; and determine a timbre attribute of the audio signal based on an inverse transform of the magnitude.

What is claimed is: 
     
       1. An apparatus comprising:
 an audio characteristic extractor to:
 determine a logarithmic spectrum of an audio signal; 
 transform the logarithmic spectrum of the audio signal into a frequency domain to generate a transform output; 
 determine a magnitude of the transform output; and 
 determine a timbre attribute of the audio signal based on an inverse transform of the magnitude. 
 
 
     
     
       2. The apparatus of  claim 1 , wherein the audio signal is part of a media signal. 
     
     
       3. The apparatus of  claim 1 , wherein the audio signal is an audio component of a video signal, further including an audio extractor to extract the audio signal from the video signal. 
     
     
       4. The apparatus of  claim 1 , wherein the audio characteristic extractor is to determine the logarithmic spectrum of the audio signal using a constant Q transform. 
     
     
       5. The apparatus of  claim 1 , wherein the audio characteristic extractor is to determine the transform of the logarithmic spectrum using a Fourier transform and determine the inverse transform using an inverse Fourier transform. 
     
     
       6. The apparatus of  claim 1 , wherein the audio characteristic extractor is to determine a timbre-independent pitch attribute of the audio signal based on an inverse transform of a complex argument of the transform of the logarithmic spectrum. 
     
     
       7. The apparatus of  claim 1 , further including an interface to:
 transmit the timbre attribute to a processing device; and 
 in response to transmitting the timbre attribute to the processing device, receive at least one of a classification of the audio signal or an identifier corresponding to a media signal corresponding to the audio signal from the processing device. 
 
     
     
       8. The apparatus of  claim 7 , wherein the interface is to transmit the at least one of the classification of the audio signal or the identifier corresponding to the media signal to a user interface. 
     
     
       9. The apparatus of  claim 1 , further including a microphone to receive the audio signal via ambient audio. 
     
     
       10. The apparatus of  claim 1 , wherein the audio signal corresponds to a media signal to be output by a media output device. 
     
     
       11. The apparatus of  claim 1 , further including an interface to receive the audio signal from a microphone. 
     
     
       12. A non-transitory computer readable storage medium comprising instructions which, when executed, cause a one or more processors to at least:
 determine a logarithmic spectrum of an audio signal; 
 transform the logarithmic spectrum of the audio signal into a frequency domain to generate a transform output; 
 determine a magnitude of the transform output; and 
 determine a timbre attribute of the audio signal based on an inverse transform of the magnitude. 
 
     
     
       13. The computer readable storage medium of  claim 12 , wherein the audio signal is part of a media signal. 
     
     
       14. The computer readable storage medium of  claim 12 , wherein the audio signal is a an audio component of a video signal, wherein the instructions when executed cause the one or more processors to extract the audio signal from the video signal. 
     
     
       15. The computer readable storage medium of  claim 12 , wherein the instructions when executed cause the one or more processors to determine the logarithmic spectrum of the audio signal using a constant Q transform. 
     
     
       16. The computer readable storage medium of  claim 12 , wherein the instructions when executed cause the one or more processors to determine the transform of the logarithmic spectrum using a Fourier transform and determine the inverse transform using an inverse Fourier transform. 
     
     
       17. The computer readable storage medium of  claim 12 , wherein the instructions when executed cause the one or more processors to determine a timbre-independent pitch attribute of the audio signal based on an inverse transform of a complex argument of the transform of the logarithmic spectrum. 
     
     
       18. The computer readable storage medium of  claim 12 , wherein the instructions when executed cause the one or more processors to:
 transmit the timbre attribute to a processing device; and 
 in response to transmitting the timbre attribute to the processing device, receive at least one of a classification of the audio signal or an identifier corresponding to a media signal corresponding to the audio signal from the processing device. 
 
     
     
       19. The computer readable storage medium of  claim 18 , wherein the instructions when executed cause the one or more processors to transmit the at least one of the classification of the audio signal or the identifier corresponding to the media signal to a user interface. 
     
     
       20. An apparatus comprising:
 means for determining a timbre attribute of an audio signal, the means for determining to:
 determine a logarithmic spectrum of the audio signal; 
 transform the logarithmic spectrum of the audio signal into a frequency domain to generate a transform output; 
 determine a magnitude of the transform output; and 
 determine the timbre attribute of the audio signal based on an inverse transform of the magnitude.